We are looking a free software for books. It is really a chore if you number every page 1-300 and a single font or spacing can lead to mistakes. So do you guys know of any book making free software to use? There are some free with a trial period and where looking for something that does not expire.

Which formats of book do you need and which OS are you using?
Scribus is by far your best free choice. If you need ePub calibre includes a decent E-book editor. The calibre E-book editor is good for editing and conversion. The best free stand alone choice would be Sigil, it's a very good ePub editor and also mature. Sigil has paused/ending development but recently there has been some renewed development of Sigil.

It has a steep learning curve, but TeX/LaTeX is a good tool. I've used it myself for a variety of large-scale projects, including full books.

I have scribus but I haven't used it much I lost interest in ever book I started.